Filler for screw holes?

[CJ]

I'm building a 16 foot plywood skiff and am looking ahead to painting the outside of the hull. The hull is constructed of marine miranti ply, which looks real nice the way it is except for the hundreds of countersunk screws throughout the boat and one butt joint. I have some WEST system epoxy, slow hardener and colloidal silica on hand. Is this the way to go to fill in these holes in preparation for painting? Does this stuff sand easily? Do I have to sand at a particular stage in the curing process, or is it just as easy when fully cured? Or, should I use something completely different?

[rrowlands]

If you (or someone in the future) ever want to take it apart for repairs it would be advisable to plug over the countersunk screws with bungs made of the same material. You might also consider removing the screws prior to installing bungs to gain a litle more depth.

[CJ]

Since this is just going to be a fishing / gunkholing / utility type boat, I don't anticipate having to remove any screws for repairs. Besides all the joints are 5200-ed together and I plan to fiberlass over the whole bottom and seams that will also cover a lot of these screws.

[Nicholas Carey]

Originally posted by CJ:
I'm building a 16 foot plywood skiff and am looking ahead to painting the outside of the hull. The hull is constructed of marine miranti ply, which looks real nice the way it is except for the hundreds of countersunk screws throughout the boat and one butt joint. I have some WEST system epoxy, slow hardener and colloidal silica on hand. Is this the way to go to fill in these holes in preparation for painting? Does this stuff sand easily?No. It doesn't sand easily. It's considerably harder than the wood and you're quite likely to get hollows around the epoxy/silica.

Or, should I use something completely different?You could use putty, like Interlux Surfacing Putty. Or, if you want to use epoxy, you should make an epoxy fairing compound out of epoxy and phenolic or glass microballoons—the West System's versions are (phenolic) 407 Low-Density filler, or (glass) 410 Microlight.

Microballoons are microscopic hollow beads/bubbles of glass or phenolic resin. They make a very light putty that's easy to sand when cured. Just mix it like you would the colloidial silica.

[ 04-14-2004, 01:07 AM: Message edited by: Nicholas Carey ]

[CaseyJones]

I'll second the West 410. Makes a great filler/fairing compound. Sands beautifully, too.

[JimD]

Like others say, don't use silica if you can help it. Use something that sands easier such as microballons. You can sand silica fair with much patience and diligence but it's a royal pain and not necessary in this case.

[buhmkin]

Yeah I'll third the West 410, or the 407.

A scraper of any kind as well as sandpaper is good on smoodge. For kicks I like to mix it up, a little scraping, a lot of sanding, and a beer an hour starting at noon.

[CaseyJones]

Starting at noon? Why wait? It's always noon somewhere. ;)

[tnert]

Might I hijack the thread and ask about filling screw holes in Cedar above the waterline? Interlux as mentioned above, bondo, hardware store wood putty? Thanks, Sorry.

[buhmkin]

Coffee 'till noon.
Beer at breakfast and I drool a little all day. Well, I guess that's the point, and I could use a little more drooling lately.

Cedar and any of the suggested fillers does it for topsides, I think. I use the epoxy smoodge described above (with 407 or 410) for pretty much all my filling/fairing needs above and below the waterline.

[CJ]

Thanks for the suggestions. Buhmkin's got the right idea. I think I'll go with that one. Does the quality become affected as the hours pass? If so, does it get better or worse? :D

[buhmkin]

That's the beauty of it, whenever I accidently get smashed it becomes impossible to mix up smoodge, so no harm's done.

Cheers.

[buhmkin]

I'll add the caveat that I don't endorse becoming accidently smashed on a regular basis. It is hard on the family and causes a most odorous and soft stool.

But so does unmoderated hull sanding, so, I dunno, all things in moderation. I think I'll have another.

[Whiffle English]

You might want to try the bee's wax and resin mix that was written about in WB about a year ago. I have used it with some success; the only difficulty is that resin is pretty expensive and there is a learning curve in removing excess. But it works great and is fast.

[paul oman]

Hi Guys

A neat quicky epoxy putty trick I've found (even though we sell epoxies and all the thickerners) -

mix in some of that hardware store, light weight ready to use wall spackle into your epoxy as a thickener and filler. (I assume it is mostly microspheres and a wee bit of binder) - anyway, result is a fine, ligjht weight epoxy putty - for that quick fix

paul oman
progressiv epoxy polymers

[CJ]

Thanks for the tips. I'll save these for future use. I did buy some West 410. Haven't tried it yet, but sounds like it'll do the trick. :rolleyes:

[Bruce Hooke]

Originally posted by tnert:
Might I hijack the thread and ask about filling screw holes in Cedar above the waterline? Interlux as mentioned above, bondo, hardware store wood putty? Thanks, Sorry.I would be inclined to use a more traditional filler for this situation -- it should be easier to remove than epoxy if you need to remove any of the screws in the future. Part of the "beauty" of traditional construction is the relative ease with which parts of the boat can be removed and replaced, so it makes sense to keep this in mind when doing things like filling screw holes.

[Keith Wilson]

FWIW, epoxy and #410 Microlight in a screw hole is relatively easy to remove, even without heat. It's fairly soft (microballoons are mostly nothing, after all) and chisels/scrapes out just about as well as more traditional putties. Epoxy with silica is quite strong and is a royal pain to remove from anything.

[Ted Ford]

Used a product - 3M Marine Premium Filler - in last year's Wooden Boat School course taught by Greg Rossel. Comes as a white resin (like Bondo filled with microballons) - mix with blue catalyst until you get a light blue goo and apply to screw holes. Used on a cedar planked skiff, it sanded easily and flush with the planking. OK for below waterline. $15 pint at Amazon.

http://www.amazon.com/exec/obidos/tg/detail/-/B0000AZ4YS/qid=1083111810/sr=1-9/ref=sr_1_9_sg/102-1254618-6080141?v=glanc e&s=sporting-goods&n=3375301

Ted